Manufacture of leather and products resembling leather.



4 UNITE str rEs PATENTOEFIOE; :j.

WERNER sran'rnnona, 0E LEIPZIG, AND KURT HAnIN 0E :HEE'sE Ln, GERMANY,

AssmNons, BY .MEsNE ASSIGNMENTS, To TH CORPORATION,ANLYDAT-LEDER;

v WERKE, AKTIENGESELLSCHAFT, 0E HEnsrELn, GERMANY.

MANUEAcTUnE LEA EEAND PRODUCTS aEsE nfING LEATHEE.

No Drawing.

To all whom it may concern:

Be it known that we, WERN R SPALTE- How, and KURT HARING,' both citizens of the German Empire, and. residents of Leipzig (with the post-oflice addressMozait strasse 21) and Hersfeld, Hesse-Nassau, (with the .post-ofiice address Dippelstrass e 4,) Germany, respectively, have invented new-and useful Improvements in the Mannfacture of Leather and Products Resembling Leather, of which the following is a specification.

3 4 The present invention relates to themanu- 4 facture of leather and leather-like products and has for its object the production of leathers having improved qualities such as to make them of increased value for ordinary uses and to render them useful for purposes for which ordinary leathers are not adapted.

The invention may be consldered as a development and enlargement of the'invention set forth in our United States Letters PatentNo. 1,066,231, July 1, 1913, and consists generally: speaking, in dehydratmg a 1 hide or skin or a preliminarily tanned leather and subsequently tanning the dehydrated material by asuitable molten agent in such a manner that the pores of the'material become substantially completely filled with the agent. The agent should be one which becomes liquid at temperatures not injurious to the hide fiber bub considerably above the temperature at which the leather is to be used.

The dehydrating is preferably accomplished by immersion 1n baths of alcohol,

acetone or the like of successively increasing strengths, and the treatment w1th the.

molten tanning agent is preferably preceded being removed meanwhile as by evaporation,

' and the resulting product is to a high detheimprovement of example, if the leather tannedin the usual '-rid, in a word, in any non-aqueous solvent. J1 di9lved substances which can beintro gree non-p orous.

Ourinventmn. has especial application to chrome leather. For

manner and not yet stuffed with fat is treat- .ed with an agent adaptedto take the place Specification of Letters Patent. 4 1

of water, such as alcohol, a new anflva lu-Q able product is obtained, which has the par ticular characteristic that it need not be fat} ted in order to prevent itslgdrying hard.

Patented Oct. 3, 191 Application filed December '13, 1912.. :Seria1 'No. 7i36,533.

Moreover, this product iscon siderably im-' I proved if it is treatedwith a solution, say,

in alcohol, of a suitable material which 1s insoluble in water, or with such material in molten condition or with such solutionfol lowed by treatment with such molten mate rial;

ing understood, of course, that various modi- A specific example of ourprocess as ap-f L- fications maybe made by one skilled in the art without departing from the spirit of the invention. L I

.Example 1: The hides unhaired'in the usual manner by means of lime water are l the two bath process. After the hides are tanned through, they are not, as is usual stuffed with fat before drying, but are stretched on frames and placed in a bath of chrome tanned by the'one bath process or. by

'alcohol of about 60. per cent. strength and then transferred successively to two or three baths of stronger alcohol, the last being of.

90-96-p'er cent. strength. The sln'ns should be left in each'bath for 24: hours, but this time can be considerably shortened by ag1-' 'tating either the hides or the bath. ,After all the water has been exchanged for alcohol,

the latter 'is distilled from the -"hides in a vacuum of 100 to 50 0 if to atmospheric-pressureand at a temperature of 2835 C. The product obtained is characterized by great pliability andis of additional and special value for all purposes in which the presence of fat or oil or the like is not perm1ss1ble, for example, .for motor vehicle tires.

A further treatment maybe carried out as follows, for the pmof the above product pose of improving the quality thereof, especially to' make it waterproof. The hides dried by vacuum distillation'and containing practically no water are placed in a solution of resin or the like in asuitable solvent, such as alcohol, aceton, benzene, benzin or turpentine, carbon disulphid, carbon tetrachlo:

duced into the hide in this manner are widely varied; for. example shellac, colophony, mastic, in factf'any resin that is soluble, also caoutchouc, guttapercha, cellulose derivatives, bituminous substances, residues from the dry distillation of coal tar and lignite tar, and even such tar itself dissolved insuitable solvents may be used, or mixtures of any of these materials in suitable proportions. All these substances have,

I so far as tanning is concerned, a common property which they retain in the leather treated with them, namely they are insoluble in water.

For the purpose principally of obtaining a softer leather than would be produced were resins, asphalt s and the like used alone, it is advantageous to add to such materials, liquid or semi-liquid substances such as oils, for instance, linseed oil, varnlshes, for instance, linseed-oil varnish, Vaseline and parafiin wax. Especially good results are obtained by using substances having an asphaltic base such as natural asphalt and artificial asphalt (petrol-goudron) dissolved in benzene. By mixin artificial asphalt with natural asphalt or ymixing artificial asphalt having ahigh melting point with- -artificial asphalt havlng a lower melting point or by the addition of one of the aforesaid liquid or semi-liquid softening substances to either kind of asphalt, a leather of any desired softness and pliability may be obtained.

When the products are made only with a solution as described, the evaporation of the solvent again produces small cavities in the product and the leather while waterproof tip. a considerable degree is not impervious to water under pressure. If this is to be avoided, either a solvent is not used and the material is applied in the molten condition, or

the process with the dissolved tanning material is used as a preliminary-treatment, a further tanning being afterward efi'ected by means of amolten material, asphalt being in the fore-front in this respect.

A form of the process will now be described, in which first a solution-of the tanning material is used and then a fused material.

Example II: The raw hide er chrome leather or fatted (or fatted and subselution may be between 33 and 50 per cent.

according to the viscosity of the fluid formed.

' may also be effected by vent will be expelled from the me ias The leather treatedwith such a solution is then placed in a molten mass, the melting waxes and the like may be used to fix the required melting point.-

', The temperature of the molten bath should be above the highest temperature to which the leather will be subjected, for sole leather, for example at least 50 to 60. C.

The higher this temperature is, the more solid will be the leather. On introducing the material into the molten mass, there is the tendency for the two liquidsto cometo equilibrium in accordance with the laws of .difiusion. The molten mass therefore wanders through the solvent into the hide and the solvent wandersout. The bath may be kept for the first 24 hours at a temperature of C. so as to let equilibrium be attained by difi'usion slowly and without much benzene escaping. r The temperature for the next 24 hours may be about 90 to 95:, at which the greater part of the benzene is given off. Care should be taken that during the first hours the temperature of the molten bath does not exceed or only slightly exceeds the boiling point of the solvent, because otherwise the solvent escapes too quickly and so the molten material if this is very viscous, does not sufliciently penetrate the leather. If the massmelts at a very high temperature a suitable pump (rotary pump) may be used for agitating it in the vessel,

desired effect is easily obtained. In this manner the solvent is driven 0E and suflicient of the molten material penetrates the leather to fill all the pores. This last step lacing the hides in a second molten bath ee from benzene. In this case it is not necessary to evacuate.- The leather is then removed from the bath and the bulk of the contents adhering to it are stripped ofi and the skin'is carefully scraped, the remaining adhering matter being finally washed 0d with benzene between two brush rollers. It is then finished in any suitable manner and dressed with a thin asphalt varnish. To fill the pores of the leather to the greatest de, it is advisable "-to choose a molten material which is soluble in the solvent employed. Otherwise, the solpores in the form of a vapor and the mass Wlll not penetrate into the finest pores to such an extent v as when the molten material is' soluble in the solvent. 'However, the of non-soluthe vessel itself being evacuated, whereby the ble materials will produce a good product, especially ifjthe molten mass isquite mobileas is the case when paraflin wax, ceresin or other waxes or artificial asphalt of low, melt. ing point. is employed. In .this 'case' the solvent may be evaporated before the molten mass treatment=is carried out or the latter maybe carried out without any preceding solution treatment. The hide, dehydrated-by not tanned at all, is characterized by its especially great resistance to high temperatures, But even leathers which have not been dehydrated with alcohol can be subjected to the difl'usion' process, provided,

Y however, that they have been dehydrated as being subjectedto a high temperature until as much water-as possible has been re.-

moved from them;-

'Ordinary chrome'leather not' dehydrated by means of alcohol, is dried for a short time at 50 C. before being impregnated with the solution, and is then subjected to "the above treatment, which however must not last, longer than 6' to 8 hours. .The.

leather vmade in this way fronrv chrome leatherdifiers from other chrome leather by the small amount of filling which it contains.

-The tanning with colophony and paraflin.

wax or ceresin or wax is effected by first impregnating with a benzene solution of leather is required it is possible to employ 20-50. perv centr strength of c'olophony which, owing to the low degree of viscosity .-of the colophony solution attains the maximum of its penetration in a few days; sub-' sequently thehide is immersed in molten parafiin wax, ceresin or wax or in a mixture of these. Accordingly as hard or soft varying quantities ofone or other of the materials. v

A special form of'the process'consists in making objects from the untanned or semitanned dried hides andthen tanning them or finishing the tanning of them, wherebymany advantages are obtained.- In the first place the soft or semi-tanned hide is more easily worked than the finished leather, and

by subsequently tanning ,the finished article its resistance to water and damp is increased, especially at the seams. This is of great importance in the shoe uppers and tires for motorv road vehicles. 1

It can be seen that the invention can be carriedput in many'other'modified ways by, combining the various .parts with each other or with other known methods or known tanning means. This is more especially possible when working with asphalt.

The leather made in accordance with our I invention, especially the product of the diffusion method, is characterized bybeingmeans of alcohol, whether it is chromedor more or less sub-- jectedto any other ,prelim1n ary tanning or ing of the hide and to the insolubility of the filling material and by being remarkably stable at high temperatures. Our asphalt leather is capable of withstanding temperatures upto 100 for 48 hours,'without. damage to' its .structure and strength.

An .important feature of the invention. which makes for such stability is the complete dehydration of the material by means water-proof, due-both tothe complete fill-j of a liquid. which has an attraction for water. .Another valuable property of asphalt leather is that it isserviceable as insulating material-I for high tension electric currents. A piece 5 m.m.' thick is only perforated by a spark produced at a potential of14,500 volts.- This leather is also remarkably resistant to pressure. A load of 2500 kilos square centimeter for five min- I utes leaves only a scarcely appreciable im pressio'n on the loaded part, and this is true whether the leather is dry or wet Chrome leather filled with an asphaltic base in accordance with our invention has the ca'-- pacity of holding-nails securely, this differing', for instance, from chrome leather filled withparaflin wfax.

" When, by this new'process, colophony and paraffin wax are introduced into chrome leather, owing to the preliminary impregnation with solution, it is possible to introduce in a ,single operation much more, colophony into the hide than by using the molten material alone. According toknown methods, the molten material'consists of 5 to 30 parts of wax or. colophony and 95 to A 70 parts of'parafiin wax or ceresin, while according to the present process a mixture of 70 parts of colophon-y and 30 parts of paraflin wax can be'easilymade within the leather. This mixture would not under ordinary circumstances penetrate the dry 'chrome-leathem at least not at the given temperature of 100 (land in the course of half an hour to an hour, while according to the new process this is quite possible without' any damage to the hide itself.

When in the claims wespeak of hides, we mean to include both hides and skins in the untanned state and the same in the tanned state, that is, leather.

,Whenin the claims we speak of resinous matter, we intend to include also the bituminous substances mentioned, which are classed as mineral resins, and such other equivalents as have been hereinbefore "enumerated.

We cla1m:

1. The process of makin, leather which COIlSlStS'lll dehydrating hi es by means of and treating the same with a' tic base.

4. The process of maln'ngleather whichconsists in dehydrating chrome leather tanned by any known PI'OCGST, and treating the same with .a molten mass containing material having an asphaltic base. 4

5.' The process of ma leatherwhich' consists in dehydratin hitfi-DS, treating 'the same with a solution 0 resinous matter and subsequently with a molten mass containing resinous matter.

6. The process of making leather which consists in dehydrating hides, by means of a suitable liquid having an attraction for water,-treating the same. with a solution of resinous matter and subsequently with a molten mass containing resinous matter.

7. The process of making leather which "consists'indehydrating chrome leather tanned by any known process, treating the same with a solution of resinous matterand subsequently with a molten mass containing resinous matter.

. 8. The process of makinglea-ther which consists in dehydrating chrome leather by means of a suitable liquid having an attraction for water, treatlng the same with a solution of resinous matter and subsequently same with a solution of resinous matter and Subsequently with a molten mass containing material having an jasphaltic base.

12. The process of making leather which consists in dehydrating hides by means of a .suitable liquid having an attraction for.

quently with a molten mass containing material having an asphaltic base.

15. The process of making leather which consists in dehydrating chrome leather by means of a suitable liquid which has an attraction for water.

16.. As a new article: of manufacture, the

flexible leather, free from fatty impregnated bodies, obtained by treatingchrome leather with'a suitable liquid havingan attraction for water, substantially as described.

' 17. As a'new article of manufacture, the flexible leather, free from fatty impregnated bodies, obtained by treating chrome leather with a suitable liquid having an attraction with a molten mass containing resinousN for water and their treating the thus formed matter. 9. The process of-,1nakin(g consists in dehydrating hi e leather which.

- a suitable liquid having an" attraction for Water" treating the same with a solution containing material having'an asphaltic base and subsequently with a molten mass con-v tainin material having an asphaltic base.

10. he process ef making leather which consists in dehydrati chrome leather by means of a suitable liq 'd having' an attrac-- tion :forv water, treating the same with a srlution containin material having. an asphaltic base and su sequently with a molten mass containing materlal having-an asphal tic base.

11. The process of making leather which consists in dehydrating hides, treating the.

s by meansof product-with resinous matter, substantially 'as described. W

18. As a new article of manufacture, the flexible leather, free from fatty impregnated bodies, obtained by treating chromeleather. I

an attraction with a suitable liquid havin e thus formed for water'and then treating product with material having an asphaltic base, substantially asdescribe In testimony that we claim the foregoing as our-invention we have signed our names.

in presence of two witnesses, this 29th day of. November, 1912.

WERNER SPALTEHOLZ. A

' KURT HARING.

Witnesses:

- Fnrrz Frscnnn,

RunoLrH Fnronn. 

